1. Fields of the Invention
The present invention relates to a universal anti-torque screwdriver head structure, and more particularly to a practical and convenient screwdriver head capable of maintaining the original tenacity, improving the rigidity of the structure to extend the service life, and fitting screws of various different specifications.
2. Description of the Related Art
In general, screwdriver head is combined with a rotating tool such as a wrench or a screwdriver (not shown in the figure) and used for screwing or securing various different screw workpieces. With reference to FIGS. 4 and 5 for schematic views of a conventional screwdriver head 10 with special design and specification and its specified screw 20 respectively, the screwdriver head 10 has a stepped recess 13 formed at an action end 11 of the screwdriver head 10 and between two adjacent pull-push wings 12 and having a very small longitudinal depth, and a stepped action hole 21 formed at the specified screw 20 and having corresponding size and shape of the action end 11, so that after the stepped recess 13 and the stepped action hole 21 are combined, the pull-push wing 12 of the action end 11 of the screwdriver head 10 with the special specification and the stepped recess 13 can be embedded into the stepped action hole 21 of the screw 20 to constitute a closely attached and multi-directionally engagement, so as to provide a good transmission of the applied force.
As we all know, a screw 30 with the common specification and generally available in the market is used extensively as shown in FIG. 6. The stepped recess 13 of the screwdriver head 10 having a general action hole 31 and provided for a screw 30 with a general specification becomes useless, mainly because the too-large action end 11 cannot be inserted successfully into the smaller action hole 31 of the screw 30 of the general specification (in other words, the two have different sizes), so as to reduce the scope of applicability, the practicality and value of the screwdriver head.
Since the stepped recess 13 has a very small longitudinal depth, torque or stress cannot be produced between an applied force and a received force (or the moment arm between the applied force and the received force is too short), and the torque strength of the action end 11 and the pull-push wing 12 may be insufficient, and the service life may be shortened (or the action end 11 may be deformed, cracked or broken easily).